Fiber intake calculator

How much fiber do I need a day?

The National Academies set an adequate intake of 14 grams of total fiber per 1,000 calories. By group: 38 g for men 19–50 and 30 g after 50; 25 g for women 19–50 and 21 g after 50.

What about pregnancy and breastfeeding?

28 g a day during pregnancy and 29 g while breastfeeding.

How much do children need?

19 g at ages 1–3 and 25 g at 4–8; boys 31 g at 9–13 and 38 g at 14–18; girls 26 g from 9 to 18.

How is it tied to calories?

The adequate intake is 14 g per 1,000 calories; the daily amounts are based on typical calorie intakes. On 2,000 calories that is 28 g.

Is there an upper limit?

No — the National Academies did not set an upper limit for fiber.

Worked example: two ways to find your number

By age and sex, a 35-year-old woman’s adequate intake is 25 g a day, rising to 28 g if she is pregnant. Turning 51 lowers it to 21 g, and for men it drops from 38 g at 50 to 30 g at 51, in line with lower typical calorie intakes after 50. By calories, multiply the calorie intake by 14 and divide by 1,000: 1,600 calories gives 22.4 g, 2,000 calories gives 28 g, and 2,500 calories gives 35 g. The two methods can disagree. Someone who eats more or fewer calories than the typical amount for their group may reasonably follow the calorie-based figure.

How do I read a food label for fiber?

The Nutrition Facts label lists dietary fiber in grams and as a percent of the Daily Value, which the FDA sets at 28 grams for fiber. A serving with 4 g of fiber is therefore 14% of the Daily Value, and 8 g is 29%. The FDA’s general guide is that 5% or less is low in a nutrient and 20% or more is high, which for fiber means about 1.4 g or less is low and 5.6 g or more is high per serving. The Daily Value is a single label reference number, while the adequate intake in this calculator depends on age, sex and life stage, so a 35-year-old woman’s 25 g is 89% of the label value.

How many servings of a 4-gram food is that?

Divide the target by the grams per serving. A 35-year-old woman’s 25 g target equals 6.3 servings of a food with 4 g of fiber, or 3.1 servings of one with 8 g, which is why mixing sources across the day is easier than relying on a single food.

What does an adequate intake mean?

The National Academies published the fiber values in 2005 as adequate intakes, with 14 g per 1,000 calories as the basis for the daily amounts in the table, and set no upper limit. How you reach the goal still matters: MedlinePlus lists whole grains, nuts and seeds, and fruits and vegetables as sources, and advises adding fiber to the diet slowly, because increasing it too quickly can cause gas, bloating and cramps.

Common mistakes with fiber targets

Using the adult value for a toddler or the other way round: the table starts at age 1 and changes at 4, 9, 14, 19 and 51. Ignoring calories: the daily amount is built around typical intakes, so a very small or very large appetite shifts the target. Counting grams of high-fiber food instead of grams of fiber; labels list dietary fiber separately from total carbohydrate. Jumping to the target overnight, which MedlinePlus warns can cause gas, bloating and cramps. And treating the figure as a limit: there is no upper limit set, but health conditions can change what is advisable, so ask your clinician.

Sources and related calculators

Sources: Institute of Medicine (National Academies), Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005), the source of the adequate intakes above; MedlinePlus, “Dietary Fiber”; U.S. Food and Drug Administration, “Daily Value on the Nutrition and Supplement Facts Labels” (28 g for fiber; the 5% and 20% guide). Related: calorie calculator, protein calculator, macro calculator and water intake calculator.

For general information only — not medical advice. Talk with your doctor or another health professional about your own health. How we check our calculators.